In the past five years, New ­England’s growing seal population has been blamed for luring great white sharks to Cape Cod beaches. Fishermen complain they have to compete against the marine mammals’ insatiable appetite for a dwindling number of fish. The relationship between seals and humans has grown so tense that five adult seals were shot in the head last year.

Now comes a broad-based effort to study one of the most common and mysterious animals off New England’s coast and help resolve ­human-seal conflicts.

A new group of some of the ­region’s major marine institutions and researchers will use science to better understand the role of seals in ­nature and how they affect the ­public.

For starters, the Northwest Atlantic Seal Research Consortium just released a report dispelling fears that defecating seals will foul beaches. The study found that, to the contrary, water quality at beaches frequented by seals is often cleaner.

“We know seals play a role in the system, but it is not well defined,’’ said Andrea Bogomolni, a ­research associate at the Woods Hole Oceanographic Institution, which is hosting the consortium. “What do they eat, where do they go, how much does fishing take away from what they eat. We don’t know a lot.”

Seals, as any visitor to Cape Cod probably knows, are making a comeback after being hunted so much that they all but disappeared from the ­region’s waters. The harbor seal population grew first, but they have now been joined by a far larger species, the 300- to 600-pound gray seal.

Scientists do not know how many gray seals reside in Massa­chusetts waters, but they know numbers are increasing. For example, in the early 1980s, only a handful of gray seal pups were seen on Muskeget Island off the western tip of Nantucket, the seals' primary breeding ground in the region. These days, thousands have been spotted there, and they are using outer islands in Maine far more than in the past, said ­Gordon Waring, a fishery biologist and seal specialist with the National Oceanic and Atmospheric Administration’s Northeast Fisheries Science Center, another consortium member.

‘We know seals play a role in the system, but it is not well defined.’

A visit to Chatham Harbor or Monomoy Island, two of their favorite places to frequent and haul out of the ocean to rest, illustrates the trend.

“It looks like seals are painted on the beach,’’ said Waring. Tours have popped so visitors can watch seals frolic.

Seals did not always delight. Seals were once considered such marine pests that hunters in Maine and Massachusetts could get $5 if they produced a seal nose and animal skin. ­Researchers estimate as many as 135,000 seals were killed in a roughly 75-year period through the early 1960s, according to a 2009 paper in the journal Northeastern Naturalist.

By 1972, the federal Marine Mammal Protection Act made it a crime to injure or harass seals and other marine mammals in US waters. The law has been so successful that growing marine mammal populations, such as sea lions in Washington and Oregon, have sparked widespread anger because they eat too many salmon, an endangered species. In California, some residents have waged a two-decade fight to evict seals from a popular swimming area.

The battles have never been as fierce in New England, but complaints have increased as beaches are closed when great white sharks, who hunt seals, are spotted. And fishermen have complained that the seals steal their catches.

Five adult gray seals were found shot to death on Cape Cod in 2011. No one has been charged in the deaths.

So far, the consortium has been meeting with fishermen, government officials, and others to understand some of the conflicts and
what they need to learn about seals.

Despite seals being a common sight off the coast, there is very little money to research them.

“Funding has been tight, and it usually comes when there is a problem with a population: The numbers are ­decreasing,’’ said Bogomolni. “We sort of have the opposite problem here.”

Scientists involved in the consortium have already launched a program in which researchers and the public can take pictures of seals that are tagged or branded and track their movements and health. The group also hopes to apply for funding and to collaborate in researching seal population, diet, movement, predation, disease, and other issues.

For ­example, Bogomolni studies how seals can be sentinels for pollution in the environment.

The most recent study on beach quality — by Rebecca J. Gast, an associate scientist at Woods Hole — found concerns about dirty beaches from seal scat ­appears to be unfounded. Not only did the study find no change in water quality near haul-out areas, it found those beaches to be cleaner than beaches without large numbers of seals nearby.

In fact, when ­researchers are on the beach looking for scat “it is really hard to find,’’ said ­Bogomolni.

The consortium includes the Provincetown Center for Coastal Studies, Riverhead Foundation for Marine ­Research and Preservation
in New York, and the University of New England Marine Animal Rehabilitation Center in Biddeford, Maine.

“Many of the questions we have about seals are big-picture questions, on the scale of an ­entire ecosystem, rather than a single beach or fishing ground,” Owen Nichols, director of the Marine Fisheries Research Program at the Center for Coastal Studies said in an e-mail.

“We also hope to work as a group to provide an unbiased source of scientific information to the public. . . . In many cases, there is a lack of available information regarding seemingly simple questions such as what or how much seals eat, or what we do or don’t know and why.”